U.S. patent application number 12/033362 was filed with the patent office on 2008-08-21 for electrophotographic printer.
Invention is credited to Jyun OGINO, Tsukasa ONOSE, Yukio OTOME, Tomohiko SAITO, Sho SAWAHATA.
Application Number | 20080199213 12/033362 |
Document ID | / |
Family ID | 39678167 |
Filed Date | 2008-08-21 |
United States Patent
Application |
20080199213 |
Kind Code |
A1 |
SAITO; Tomohiko ; et
al. |
August 21, 2008 |
ELECTROPHOTOGRAPHIC PRINTER
Abstract
An electrophotographic printer capable of easily attaching and
detaching a retaining means to retain the inside of a
photoconductive drum to and from the photoconductive drum. A flange
located on the extraction side of a photoconductive drum is
provided with: a retaining means to support the photoconductive
drum from the side of the inner circumferential face of the
photoconductive drum. And an advance and retreat mechanism to
advance and retreat the retaining means to and from the inner face
of the photoconductive drum. The retaining means can be easily
dismantled from the photoconductive drum by operating the advance
and retreat mechanism, and thereafter extracting the flange from
the photoconductive drum.
Inventors: |
SAITO; Tomohiko;
(Hitachinaka, JP) ; ONOSE; Tsukasa; (Hitachinaka,
JP) ; SAWAHATA; Sho; (Hitachinaka, JP) ;
OTOME; Yukio; (Hitachinaka, JP) ; OGINO; Jyun;
(Hitachinaka, JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
39678167 |
Appl. No.: |
12/033362 |
Filed: |
February 19, 2008 |
Current U.S.
Class: |
399/117 |
Current CPC
Class: |
G03G 15/757 20130101;
G03G 15/751 20130101; G03G 2221/1606 20130101 |
Class at
Publication: |
399/117 |
International
Class: |
G03G 15/08 20060101
G03G015/08 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 19, 2007 |
JP |
2007-037982 |
Claims
1. An electrophotographic printer, comprising: a cylindrical
photoconductive drum having photosensitivity; a first flange
engaging with an end of said cylindrical photoconductive drum and
being supported by a drive shaft of the printer; and a second
flange engaging with the other end of said cylindrical
photoconductive drum and being supported by said drive shaft, and
the printer being configured so as to concentrically fix said
photoconductive drum to said drive shaft by pressurizing said
second flange toward the side of said first flange through a
tightening means, wherein said second flange includes a retaining
means configured so as to retain the inner circumferential face of
said photoconductive drum and be able to advance to and retreat
from the inner circumferential face.
2. An electrophotographic printer, comprising: a cylindrical
photoconductive drum having photosensitivity; a first flange
engaging with an end of said cylindrical photoconductive drum and
being supported by a drive shaft of the printer; and a second
flange engaging with the other end of said cylindrical
photoconductive drum and being supported by said drive shaft, and
the printer being configured so as to concentrically fix said
photoconductive drum to said drive shaft by pressurizing said
second flange toward the side of said first flange through a
tightening means, wherein said second flange includes: a retaining
means configured so as to retain the inner circumferential face of
said photoconductive drum; and an advance and retreat mechanism to
advance and retreat said retaining means to and from the inner
circumferential face of said photoconductive drum.
3. An electrophotographic printer according to claim 2, wherein
said retaining means is involving a resilient means configured to
advance and to retreat the retaining means to the inner
circumferential face of said photoconductive drum.
4. An electrophotographic printer according to claim 2 wherein said
retaining means has a contacting member to contact the inner
circumferential face of said photoconductive drum, and is provided
with a contacting force adjusting means to adjust the contacting
force of said contacting member against said photoconductive
drum.
5. An electrophotographic printer according to claim 3, wherein
said retaining means has a contacting member to contact the inner
circumferential face of said photoconductive drum, and is provided
with a contacting force adjusting means to adjust the contacting
force of said contacting member against said photoconductive
drum.
6. An electrophotographic printer according to claim 5, wherein
said contacting force adjusting means is configured so as to adjust
the resilient force of said resilient means.
7. An electrophotographic printer, comprising: a cylindrical
photoconductive drum having photosensitivity; a first flange
engaging with an end of said cylindrical photoconductive drum and
being supported by a drive shaft of the printer; and a second
flange engaging with the other end of said cylindrical
photoconductive drum and being supported by said drive shaft, and
the printer being configured so as to concentrically fix said
photoconductive drum to said drive shaft by pressurizing said
second flange toward the side of said first flange through a
tightening means, wherein said second flange includes: a retaining
means configured so as to retain the inner circumferential face of
said photoconductive drum and be able to advance to and retreat
from the inner circumferential face; and engaging parts to engage
with said retaining means when said retaining means advances on the
inner circumferential face of said photoconductive drum.
8. An electrophotographic printer according to claim 6, wherein
said retaining means has rods that can advance to and retreat from
the inner circumferential face of said photoconductive drum, and
engaging grooves to engage with end parts of said rods are formed
on the inner circumferential face of said photoconductive drum.
9. An electrophotographic printer according to claim 7, wherein
said engaging grooves are formed all around the inner
circumferential face of said photoconductive drum.
10. An electrophotographic printer, comprising: a cylindrical
photoconductive drum having photosensitivity; a first flange
engaging with an end of said cylindrical photoconductive drum and
being supported by a drive shaft of the printer; and a second
flange engaging with the other end of said cylindrical
photoconductive drum and being supported by said drive shaft, and
the printer being configured so as to concentrically fix said
photoconductive drum to said drive shaft by pressurizing said
second flange toward the side of said first flange through a
tightening means, Wherein said first flange includes an outer
circumferential part to retain the inner circumferential face of
said photoconductive drum and an end engaging with an end of said
photoconductive drum on the printer side; said second flange is
provided with a fixed part supported by said drive shaft, plural
retaining arms extending from the fixed part in the radial
direction and retaining the inner circumferential face of said
photoconductive drum, a connecting member extending from the
retaining arms to the side where said photoconductive drum is
extracted, an outer circumferential part being formed at the
extending end of said connecting member and retaining the inner
circumferential face of said photoconductive drum, and an end
engaging with the end on the side where said photoconductive drum
is extracted; and also said retaining arms includes rods advancing
to and retreating from the inner circumferential face of said
photoconductive drum, retaining seats formed at the tips of said
rods, and an operation part to advance and retreat said rods.
11. An electrophotographic printer according to claim 9, wherein
each of said retaining seats is pressed with resilient force at the
time of contacting the inner circumferential face of said
photoconductive drum.
12. An electrophotographic printer according to claim 9, wherein:
each of the outer circumferential parts of said first flange and
said second flange to retain the inner circumferential face of said
photoconductive drum has a conically shaped surface; and the
diameter of the cone having said conically shaped surface decreases
toward the direction where said photoconductive drum is clamped.
Description
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese
application serial No. 2007-37982, filed on Feb. 19, 2007, the
content of which is hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an electrophotographic
printer and in particular, an electrophotographic printer wherein
an attachable and detachable mechanism of a photoconductive drum is
improved.
[0004] 2. Description of the Related Art
[0005] In general, the photoconductive drum of an
electrophotographic printer is configured as disclosed in e.g. JP-A
No. 502130/1990. The configuration is explained in reference to
FIGS. 9 and 10.
[0006] A photoconductive drum 1, configured in a cylindrical shape,
engages with the outer circumference of a first flange 3 fixed to a
step formed between a drive shaft 2 and a small diameter part 2S of
the drive shaft 2 on the side of an end of the cylinder in a
electrophotographic printer. Meanwhile, the end on the other side
of the cylinder engages with a second flange 4 attached to the
small diameter part 2S of the drive shaft 2.
[0007] Then the photoconductive drum 1 is concentrically supported
on the drive shaft 2 and firmly retained between the first flange 3
and the second flange 4. A tightening means 5 such as a nut screwed
at an end of the small diameter part 2S tightens the first flange 3
and second flange 4. Also, the first flange 3 is integrally
provided with plural ribs 3R that extend in the axial direction and
the end of the ribs 3R is located close to the second flange at the
time of tightening. The ribs 3R function as a guide means so that
the photoconductive drum 1 may not contact peripheral devices when
the photoconductive drum 1 is attached to or detached from the
drive shaft 2.
[0008] In addition, a retaining means 6 is attached so as to
contact plural portions located in the circumferential direction on
the inner circumferential face of the photoconductive drum 1 in
order to prevent distortion of the photoconductive drum 1. The
retaining means 6 is provided with halved support pieces 6A and 6B
having plural contact parts contacting the photoconductive drum 1.
And spring members (not shown in the figures) to press the support
pieces 6A and 6B into contact with the photoconductive drum 1 by
spring pressure.
[0009] The electrophotographic printer has the retaining means
inside the photoconductive drum and the photoconductive drum is
replaced together with the retaining means when it is replaced.
From the view point of resource conservation therefore, the
retaining means has been discarded in vain.
[0010] To cope with the problem, it is one solution to reuse a
retaining means by dismantling the retaining means from an old
photoconductive drum and then attaching the dismantled retaining
means to a new photoconductive drum at the time of the replacement
of the photoconductive drums. However, photoconductive drums are
replaced by end-users in almost all cases, furthermore special
tools are used for detaching or attaching the retaining means from
or to a photoconductive drum, and hence the replacement of the
photoconductive drum is very difficult and needs a long time.
[0011] An object of the present invention is to provide an
electrophotographic printer capable of easily attaching and
detaching a retaining means to retain the inside of a
photoconductive drum to and from the photoconductive drum.
SUMMARY OF THE INVENTION
[0012] In the present invention, in order to attain the above
object, an electrophotographic printer is provided with: a
retaining means to retain a photoconductive drum from the side of
the inner circumferential face of the photoconductive drum at a
flange located on the extraction side of the photoconductive drum;
and an advance and retreat mechanism to advance and retreat the
retaining means inside the photoconductive drum.
[0013] With the above configuration, it is possible to easily
dismantle a retaining means together with a flange from a
photoconductive drum by releasing the contact between the retaining
means and the photoconductive drum by the operation of the advance
and retreat mechanism and thereafter extracting the flange provided
with the retaining means from the photoconductive drum when the
photoconductive drum is dismantled. Consequently, it is possible to
easily mount a retaining means together with a flange on a
photoconductive drum by operation through the reverse procedure
when the photoconductive drum is mounted.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a vertical sectional view of a photoconductive
drum showing the first embodiment of the present invention.
[0015] FIG. 2 is a vertical sectional view showing the
photoconductive drum is on the way of extraction.
[0016] FIG. 3 is a vertical sectional view showing the flange on
the extraction side is detached from the photoconductive drum.
[0017] FIG. 4 is a sectional view taken on line IV-IV of FIG.
3.
[0018] FIG. 5 is a enlarged vertical sectional view showing the
flange on the extraction side is attached to the inner
circumferential face of the photoconductive drum.
[0019] FIG. 6 is a enlarged vertical sectional view showing
residing immediately before the flange on the extraction side is
detached from the inner circumferential face of the photoconductive
drum.
[0020] FIG. 7 is a vertical sectional view showing a second
embodiment where the flange on the extraction side is attached to
the inner circumferential face of the photoconductive drum.
[0021] FIG. 8 is an enlarged vertical sectional view showing a
substantial part in the view shown in FIG. 7.
[0022] FIG. 9 is a vertical sectional view showing a conventional
photoconductive drum and corresponding to FIG. 1.
[0023] FIG. 10 is a vertical sectional view taken on line X-X of
FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] An embodiment of an electrophotographic printer according to
the present invention is hereunder explained in reference to FIGS.
1 to 6.
[0025] In FIG. 1, a photoconductive drum 1 is rotatably supported
by a drive shaft 2 in a printer (not shown in the figures). A small
diameter part 2S extends from the root of the drive shaft 2 toward
the side where the photoconductive drum 1 is extracted. The outer
circumference of a first flange 3 fixed to the step formed between
the drive shaft 2 and the small diameter part 2S engages with an
end part of the cylindrical photoconductive drum 1. More
specifically, an outer circumferential part 3S is formed on the
first flange 3. And the outer circumferential part 3S fits into the
inner circumferential face of the photoconductive drum 1 and
thereby contacts and supports the inner circumferential face of the
photoconductive drum 1. Furthermore, an end part 3E of the outer
circumference part 3S engages with an end of the cylindrical
photoconductive drum 1 all over the circumference so that the
photoconductive drum 1 may not move toward the axial support side
of the drive shaft 2.
[0026] In FIG. 1 and 2, the other end of the cylindrical
photoconductive drum 1 engages with a second flange 4 attached to
the small diameter part 2S in the manner of being attachable and
detachable only in the axial direction. More specifically, the
second flange 4 comprises a fixed part 7 attached to the small
diameter part 2S in the manner of being attachable and detachable
only in the axial direction. And plural retaining arms 8 is
provided in the second flange 4 which extend from the fixed part 7
in the radial direction and retain the inner circumferential face
of the photoconductive drum 1. A conical connecting tube 9 is
provided which is extending from the retaining arms 8 toward the
side where the photoconductive drum 1 is extracted. In FIG. 3, an
annular shaped outer circumferential part 4S that is formed at an
end of the connecting tube 9, fits into the inner circumferential
face of the photoconductive drum 1. The outer circumferential part
4s contacts and supports the inner circumferential face of the
photoconductive drum 1. And an annular shaped end part 4E is
engaged with an end of the cylindrical photoconductive drum 1 all
over the circumference. The annular shaped outer circumference part
4S and the end part 4E maybe connected directly to the fixed part 7
not through the connecting tube 9 but through another arm.
[0027] Then the photoconductive drum 1 is concentrically supported
by the drive shaft 2 in the manner of being clamped and retained by
the first flange 3 and the second flange 4 when the fixed part 7 is
tightened by tightening means 5 such as a nut screwed at the end of
the small diameter part 2S.
[0028] In addition, the first flange 3 is provided with plural ribs
3R that extend in the axial direction and have extended end parts
located at positions close to the second flange at the time of
tightening. The ribs 3R function as a guide means so that the
photoconductive drum 1 may not contact peripheral devices when the
photoconductive drum 1 is attached to or detached from the drive
shaft 2.
[0029] In the meantime, it is important that: each of the outer
circumference part 3S of the first flange 3 and the outer
circumference part 4S of the second flange 4, those fitting into
the photoconductive drum 1, has a conically shaped surface and the
diameter of the conically shaped surface decreases toward the
direction where said photoconductive drum is clamped. Accordingly,
no gap maybe formed between the outer circumference parts 3S and 4S
and the photoconductive drum 1 at the time of fitting. In other
words, when the first flange 3 and the second flange 4 are
tightened with the tightening means 5, and thereby print quality is
prevented from deteriorating due to the eccentricity of the
photoconductive drum 1 caused by the formed gap.
[0030] In FIG. 3 to FIG. 6, addition, each of the retaining arms 8
includes a rod 10 retained movably forward and backward in the
radial direction and a retaining seat 11 is disposed at a tip of
the rod 10. A friction member 12 made of rubber material or the
like is disposed on the retaining seat 11 on the side contacting
the inner circumferential face of the photoconductive drum 1 in
order to ensure the retaining of the photoconductive drum 1.
Further, a resilient means such as a tension spring 13 is placed
around the rod 10 in order to give the retreating force of the
retaining seat 11. And each of the retaining arms 8 has an
eccentric cam 14. The eccentric cam 14 has the function of
advancing and retreating the rod 10 to and from the photoconductive
drum 1. Here, the retaining seat 11 works as a contacting member
which contacts the inner circumferential face of the
photoconductive drum 1 according to the present invention. Then the
eccentric cam 14 acts as a contacting force adjusting means to
adjust the contacting force of the contacting member against the
photoconductive drum.
[0031] Here, the retaining means according to the present invention
comprises the retaining arms 8, the rods 10, and the retaining
seats 11, and the advance and retreat mechanism. The mechanism
advances and retreats the retaining means to and from the inner
circumferential face of the photoconductive drum which comprises
the tension spring 13, the eccentric cams 14 and the handles
15.
[0032] Successively, operations for changing the photoconductive
drum 1 are explained.
[0033] Now the photoconductive drum 1 mounted in a printer is
retained on the drive shaft 2 by the clamping force between the
first flange 3 and the second flange 4 as shown in FIG. 1. On this
occasion, each of the retaining arms 8 presses a retaining seat 11
to the inner circumferential face of the photoconductive drum 1
with an eccentric cam 14 against the tension of a tension spring 13
as shown in FIG. 5. When the photoconductive drum is detached from
the printer in this state, it is possible to extract the
photoconductive drum 1 outside the printer as shown in FIG. 2 by
firstly loosening and detaching the tightening means 5 in the state
shown in FIG. 1 and thereafter pulling and extracting the first
flange 4 while the ribs 3R of the first flange 3 are used as guides
and the photoconductive drum 1 does not contact the peripheral
devices.
[0034] Successively the second flange 4 is detached from the
photoconductive drum 1 extracted outside the printer. The second
flange 4 is detached from the drum 1 by extending a hand into the
opening side of the connecting tube 9 and rotating the handle 15
disposed on each of the retaining arms 8.
[0035] The pressing force of each rod 10 caused by each eccentric
cam 14 is released by the rotation of the handle 15 as shown in
FIG. 6. When the pressing force of each rod 10 is released, each
retaining seat 11 is separated from the inner circumferential face
of the photoconductive drum 1 by the retracting force of the
tension spring 13. The retaining arms 8 can also be extracted
simultaneously as shown in FIG. 3 by holding the second flange 4
and extracting from the photoconductive drum 1 in this state
Thereafter, when a new photoconductive drum 1 is attached to the
printer, the second flange 4 engages with an end of the new
photoconductive drum 1 as shown in FIGS. 2 and 3. By the rotation
of the handle 15, the retaining seat 11 is displaced to the side of
the photoconductive drum 1 as shown in FIG. 5 by the pressing force
of the rod 10 caused by the eccentric cam 14. And the retaining
seat 11 is pushed to the inner circumferential face of the
photoconductive drum 1. The second flange 4 is fixed again to the
end of the photoconductive drum 1 on the extraction side.
[0036] Successively, the second flange 4 is held and the
photoconductive drum 1 is attached to the printer while being
guided by the ribs 3R of the first flange 3 as shown in FIG. 2.
Thereafter the tightening means 5 is attached to the small diameter
part 2S, the attached photoconductive drum 1 is tightened, and
thereby the photoconductive drum 1 is concentrically fixed to the
drive shaft 2 by the clamping force between the first flange 3 and
the second flange 4 as shown in FIG. 1.
[0037] In the meantime, it is possible to increase or decrease the
force for pushing a retaining seat 11 to the inner circumferential
face of the photoconductive drum 1 by changing the rotation angle
of a handle 15, in other words by changing the rotation position of
an eccentric cam 14.
[0038] Here, although the above embodiment is the case where a
tension spring 13 is disposed on each retaining arm 8 and tension
is always imposed on each retaining seat 11 in the manner of
separating from the photoconductive drum 1, it is also possible to
impose pressing force to always push each retaining seat 11 on the
side of the photoconductive drum 1 with a compression spring in
place of the tension spring 13. On this occasion however, it is
necessary to adopt a mechanism for pulling back each rod 10 in the
direction of separating from the inner circumferential face of the
photoconductive drum 1 with each eccentric cam 14 within the
rotation range of each handle 15.
[0039] Consequently, the tension spring 13 or the compression
spring, which corresponds to the spring means of the invention. The
retaining means including the spring means contacts the inner
circumferential face of a photoconductive drum according to the
embodiment.
[0040] As explained above, in the present embodiment, since the
photoconductive drum 1 is configured so as to be attachable to and
detachable from the retaining arms 8 even by simple rotating
operation of the handles 15, it is not necessary for each
photoconductive drum 1 to have its own disposable retaining arms
8.
[0041] Note that, the weight of the photoconductive drum 1 is about
5 kg and hence it is necessary to surely hold the photoconductive
drum 1 with both hands at the attaching and detaching operation
also from the viewpoint of safety.
[0042] To that end, it is possible to facilitate the attaching and
detaching operation and handle the photoconductive drum 1 safely
during the attaching and detaching operation and after the
detaching from a printer. It can be achieved by disposing arcuate
handles 16 in the manner of connecting adjacent retaining arms 8
with each other as shown in FIG. 4.
[0043] As a modified example, it is also possible to form engaging
grooves 17, in place of the friction members 12, on the inner
circumferential face of the photoconductive drum 1 which the rods
10 contact as shown in FIGS. 7 and 8. And thereby make the rods 10
engage with the engaging grooves 17. Here, when the relative
position of the second flange 4 in the circumferential direction of
the photoconductive drum 1 is not specified, an engaging groove 17
is formed all around the inner circumferential face of the
photoconductive drum 1.
[0044] Further, the rods 10 may engage or disengage with the
engaging grooves 17 by rotating the handles 15 and thereby directly
advancing or retreating the rods 10, or by advancing or retreating
the rods 10 through eccentric cams or the like.
[0045] In the above modified example too, the same effects can be
obtained with nearly the same operations as the aforementioned
embodiment.
* * * * *